steve..everything is upgradable, they are just parts.

Honestly tho, sounds to me that you had best start out stock to see if you even like the ride as opposed to the "fad". If as a new person you are immediately looking for "Deep V's" is it about "riding fixed" or being seen "riding fixed"or are you looking to simply perform tricks while hanging out with your crew? Nothing wrong with wanting to take things light, have fun and join a 'tribe'; truth is we all started somewhere, but do yourself a favor and just visit the bikeshops to look about and ask questions and get familiar, read this forum as thoroughly as you can manage, it will give you insight and help with everything and also tune you into the personality of things here which might help you avoid remarks to your queries that will be decidedly unhelpful to everyone.

If you haven't ridden fixed yet you just might get a rude awakening when you start riding down a hill and have to figure out how to stop...which has it's own major challenges until mastered, so if you do decide to get one do yourself a favor and avoid cool points by making sure you put your brakes on. There are any number of scenarios out there where putting the health and safety of yourself and others needs to be priority one.

walk before you run!

Forgive if I make presumptions but the question as to the ability to pedal backwards was somewhat scary..but I could be wrong.